Planar Juggernaut

Introduction

Letshuoer from China is a boutique audiophile company that mainly focuses on making HiFi in-ears that always strive for an audio perfection which I am truly fond of. They are very consistent with their releases and they rarely miss the target of producing quality products which is proven like the now legendary S12 Pro, Ej07m, DZ4, D13 and many more products that have been very well received around the globe. Letshuoer has now decided to extend their planar line after the S12 Pro and introduce a new upgrade aptly named the S15 that has a self develop 14.8mm planar magnetic driver along with their innovative R-Sonic 6mm passive filtering module that has been debuted on the DZ4 to give more control the bass frequency. Ivy from Letshuoer has kindly sent us a pair of S15 for an honest evaluation and we are truly grateful for the opportunity given. How will they fare in this ever growing planar segment and will they dethrone the S12 Pro? We shall find out here.

Functions & Specifications

Before we start the review, here are the specifications of the Letshuoer S15;

• Third Generation 14.8mm Planar Driver + 6mm R-Sonic Passive Filtering Module
• 30 Ohms, 106 dB Sensitivity
• 20 – 40 khz Frequency Response Range
• New Acoustic Structure
• Dual Acoustic Tubes With Filter Crossover
• High-precision 3D-printed Front Cavity
• CNC Precision Carved Aluminum Alloy Panel
• Lightweight Ergonomic Design, Fine And Delicate Touch
• 216-strands Silver-plated Monocrystalline Copper Cable
• Detachable 2.5mm, 3.5mm, 4.4mm 90-degree Angle Connectors
• 0.78mm Dual-pin receptacle

Retail Price & Where to Get

The Letshuoer S15 can be purchased from their store and in various platforms starting from December 1st at USD 329;

https://letshuoer.net/products/letshuoer-s15-third-generation-14-8mm-planar-driver-r-sonic-passive-filtering-module-hifi-wired-in-ear-monitor

Packaging & Accessories

The packaging received is quite small but they might be deceiving as they are packed neatly to the brim with all the necessities and more. Their unboxing is great as the product is well displayed neatly and with a drawer style box encasing the accessories. It came with 6 pairs of eartips which 3 pairs of balanced with a normal bore size, 3 pairs of vocals eartips which has larger bore, a blue round case, some paperworks with a tech theme poster, the IEM, a modular cable with 2.5mm, 4.4mm and 3.5mm plugs. Nice presentation indeed.

Design

The design is good with a techy feel with a 3D printed body with a medium in size and they have a matte feel similar to the DZ4 which is comfortable as they don’t stick to your ear concha but they do reduce the isolation in a small way. The faceplate is an anodized aluminium alloy in metal grey carved with their new techy logo design.

Inside the S15 we have a 3rd generation dual chamber 14.8mm planar magnetic driver along with a 6mm passive radiator tweaked and made specifically for the S15 to be a filter (passive filtering module) which is named R-Sonic. It is a unique combination never seen before and they are in charge of controlling the bass and also gives some extra extension to them. Both of these drivers are created by Letshuoer by their talented, innovative engineers which is amazing as it gives them more control over the end product.

Here’s more info on the PFM;

https://letshuoer.net/blogs/news/letshuoer-r-sonic-dynamic-harmonics?fbclid=IwAR0VjNcVG9U9gLJokpFPi0W1TLce76hciNVQCu3_LP944Lqwg197ZMJHUjw

The nozzle is quite short and large in diameter and they are fitted with a metal mesh for protection.

There are a total of 6 pairs of eartips that consist of 3 pairs of vocals, large bore eartips in blue and 3 pairs of balanced normal size bore in white, all in small, medium and large sizes.

They come with a matte blue case that is made from plastic with the same matte feel and colour of the S15 body. I do find the case practical for protection and for easy storage for the IEM.

The S15 has a standard 0.78mm 2 pin type connectors and it is an ‘L’ shaped, angled modular cable that comes with 2.5 mm balanced, 4.4 mm balanced and 3.5 mm single ended with a solid, minimalistic design. They are a 4 core twisted OCC cable that has silver plating in black and silver colour. The cable does sound pretty decent with an enhanced clarity sound and they are very practical for usage as they are light, thin and pliable.

Gears Used for Comparisons

Songs List

Tone and Presentation

The tone of the S15 is a neutral warm sound that leans towards a brighter side of the spectrum with an energetic U shaped sound due to a healthy boost in their bass and high region. They have an aggressive sound that is similar to the S12 Pro but they possess better extension on both ends along with greater overall technicalities. The overall sound here is thick and packed with details all around with a vivid planar driver resolution. They have a fun sound that is lively, uplifting and fun while being technically solid at the same time, very well suited for EDM, jazz and hip-hop.

Soundstage

The S15 possesses an expansive soundstage that is both wide and tall even for their price range. Soundstage here is quite holographic with an accurate placement of sound. They do possess a decent air in their presentation making them sound rather pleasing for most genres including movies and gaming assisted by their immersive sound. They also do have a good sized headroom that actually gives a large room feel even for an IEM giving a full sound without any boxy feel.

Separation and Timbre

Separation is amazing with no crosstalk issues producing a great left and right separation that gives music a wider range of sound along with a good layering. Timbre here is breathy, intense and aggressive but managed to be smooth overall. There is some planar metallic timbre at the top end though that is typical of this type of driver but it is minimal and doesn’t really affect the outcome but for a pure timbre performance, users might want to stick with a pure dynamic driver setup.

Drivability

The wind is rated at 30 ohms at 106 dB sensitivity which means they aren’t as sensitive to pick up noise like most balanced armature sets out there and can be driven to adequate loudness with any source but they do need some driving power to sound the best. Being underpowered, the S15 do sound a little veil in their bass section and a good warmish source matching will smoothen out the sound making it less harsh to listen to. The S15 is forgiving in their tracks selection where any type of files be it streaming or ‘hires’ playback will sound good although they do sound better with high bitrates files marginally.

The Bass (Low)

The star of the show in my opinion is the bass as it has all the quantity and the quality as well without a doubt. It is a true planar response type of fast bass that is big to say the least with an expansive bass that is hard hitting, authoritative, meaty and aggressive without overpowering issues. They do possess a good level of clarity without any muddiness issues along with a decent amount of details intact and all sounded full, clean and clear typical of a planar type bass. The bass is sufficient for normal bassheads as it does deliver a head shaking amount when called upon while still being able to be very well controlled as the passive radiator implementation is actually working decently. The texture might not be the best but it is still capable of showing layers of bass while still giving a boomy, fast bass response. Bass has excellent extension and it goes deep with a good sense of air coming in the mix. Sub-bass here is also superb with a great extended rumble that is immersive and it blends well with the big quality bass.

The Mids

Midrange is a neutral warm mids that has a thick and a mild forwardness sound to them while possessing a detailed and vivid presentation. Details here are good especially in the macro details department but the micro details are a little lacking. The mid-range have a good balanced sound that projects sound nearer to your ears resulting in a more intimate kind of music. Resolution here is superb with an excellent vividness that is the prowess of a good planar driver. Transparency is good with all sound presented without any veil or haze issues. Vocals are presented with a great intimate, soulful presentation and they are very well balanced for male or female vocals but they do lack some space due to their forward signature leaving some vocals sounding a little cramp. There is a mild coloration present here in the mid-range giving a livelier, lusher, fun sound that is very enjoyable without any major altercation in their natural state.

The Highs

High range has a neutral to bright tone that is forward and strong but well controlled with minor instances of peakiness but possesses no harshness or shout with a lively sound that has  a decent amount of detail. Clarity here is superb and the high range nuances are well displayed with a crisp sound and a sweet, strong sparkle that gives music a lively, energetic emotion that is very enjoyable. There is some setback with the crispness as it does have a minor metallic sound that plagues planar drivers but it is still capable of sounding natural enough without any distraught. They do have a borderline sibilance high range that might deter treble sensitive users but they are fine for me and I do find the high range excitingly enjoyable. Extension here is good with a slow roll-off that possesses a good decay and they are indeed airy. The treble here is quite intense indeed but not overpowering like the bass response and it contributes to the high energetic sound of the S15 overall which I am fond of. Fatigue here might set in on higher volume but on normal volumes they are fine. Overall, the intensity of the high range is actually unique and very well tuned to blend with the forward midrange and big bass response of the S15 making them a true energetic planar IEM.

Comparisons

VS TangZu Wu Ze Tian Heyday

The Heyday is the current top planar IEM from TangZu audio china and they are made with collaboration with HBB and they are touted as one of the best sounding planar in its price range. They have a well balanced neutral sound that is wide and quite balanced sounding overall. Both do possess some planar timbre but in a minimal way so it does not affect the naturalness of music played.

High range

Highs on the S15 has the edge of sounding more crisp and has a more evident, sweeter sparkle. Details and clarity of both is on par but the S15 does sound more energetic and has better extension.

Midrange

The S15 midrange has a thicker presentation with a greater, more vivid resolution and transparency while the Heyday has a more neutral balanced style of presentation that is slightly more spacious. Vocals on the S15 do sound lusher and soulful while the Heyday sounded more natural.

Bass

Bass on the S15 has the winning hands of being more in their quantity as they do sound bigger, meatier and have more aggression while still having a detailed presentation. The Heyday bass is more forgiving and sounded a tad more natural overall. Airiness and extension is better on the S15 along with a deeper sub-bass extension.

Soundstage

The soundstage on both is actually quite similar with a wide and tall presentation with a decent big room effect.

VS Tinhifi P1Max Panda.

The Panda is the 3rd iteration of the P1 line that is one of the first adopters of the planar driver in IEMs. They are the most easy driving planar IEM in the P1 series and they have a more reachable price that has superb price versus performance index in the planar segment.

High region

The highs of the S15 again has the edge of being stronger, crisper and has a sweeter sparkle. Details and clarity of the S15 is slightly better but the Panda sounded more natural, less metallic sounding and slightly more air than the S15. Extension on the S15 is also

Midrange

Midrange on the S15 is thicker and warmer versus the neutral bright-ish mids of the Panda. The S15 does sound more intimate and lusher with a more forward sound and they have better transparency and resolution overall. Details and clarity on the S15 is also slightly better.

Bass

The amount of bass in both is actually quite similar with the Panda possessing a leaner bass but the quality of bass on the S15 dies sound better with more details and it is cleaner overall. The S15 bass does sound more aggressive with a more joyful bass response that is more fun to listen to along with a deeper sub-bass extension.

Soundstage

Soundstage height and depth is better on the S15 with a similar big headroom size and both have a good air in their presentation.

Synergy

Questyle M15

The Questyle M15 is my go-to portable DAC/amplifier as they are superb with Questyle’s signature direct current amplification. They are a neutral to bright sounding device suitable for a portable usage and they possess a great extension on both ends displaying none of the usual Sabre chip hump.

Bass sounded clearer and tighter with details and clarity increased. Their bass is actually slightly leaner and has a better texture. Sub-bass depth remained mostly the same but they do sound cleaner and clearer overall.

Midrange is clearer with better transparency and more vivid than while retaining the thickness and their resolution. Vocals sound lusher and more brilliance is added with a more spacious feel.

High range has a better, sweeter sparkle and they are more extended along with a reduction in their metallic sound. Treble has slightly toned down in intensity but they are still very well controlled with an increase in their airiness.

Soundstage has seen improved width and height.

Overall, they are quite suited for each other as they do add some control in their overall aggressiveness while giving a cleaner overall sound.

FiiO Q7

The Q7 is a beast of a battery driven DAC amplifier that is the top of the line in the Q series in FiiO. They are equipped with a single Sabre ES9038pro dac chip along with dual THX 788+ boasting a 3000 mw power with the DC adapter. They have a bright to warm sound that has tons of power to drive any IEMs and most of the headphones around.

Bass in terms of their texture is better and they have a tighter bass slam. They have a cleaner sub-bass extension with a slightly deeper rumble. Details and texture stayed mostly the same but they do sound airier with a more natural bass response.

Midrange has a more intimate presentation along with a slightly better, clearer transparency. They might make music a little too forward for my taste but they do sound intimately lusher, more organic with vocals pulled closer to the ears. Micro details seem more evident while macro details stay the same. The midrange also does sound more spacious with some air added into the mix.

Highs is a little more sparkle added and has a better extension along with a clearer, crisper sound added. Details and clarity stayed the same but they sounded fuller with an airier presentation. They are still borderlining a sibilant high range but managed to sound very well in control.

Soundstage height and width is better with a wider, airier sound overall.

Overall, they do have a good synergy as the Q7 does add a cleaner overall sound while still managing to sound energetic and in control especially in the bass and highs region.

Who Is It For?

The Letshuoer S15 is for someone seeking a fun planar sound that is boasting their aggressive, energetic sound that is both fun and highly technical. They do have a big bass response with a very well controlled bass that might suit light bassheads but not seeking for an earth shaking experience. They do have a strong high range with an intense treble and they may suit treble heads alike. They aren’t suited for those who seek a monitoring IEM as they aren’t clinical enough but for those who want excitement while still having great technical aspects, the S15 is surely for you. The S15 is also very suited for gaming and movies for their immersive, accurate sound placements.

Final words

The endeavour for an ultimate planar IEM that Letshuoer has been burning midnight oil has certainly paid off here as the S15 is surely in my top planar list dethroning all the planar IEM within this price range. They are certainly a beast when it comes to resolution vividness, well controlled big bass response, a thick immersive midrange and an energetic high range that is uber fun to listen to in any genre. They have it all when it comes to its minimalistic packaging, a great solid design all the way to their amazing modular cable and they are set to go from the box. The evolution of their 6 mm R-Sonic passive filter is salutable as they are an innovation that made a big improvement in their sound and it is surprisingly good in providing a better control in the overall sound output. Though the planar timbre is slightly audible, they do give a crisp and fun sound that I couldn’t stop listening to. A superb job by the team from Letshuoer by raising the bar in the planar segment and they deserve a product recommendation.

I would rate this product 4 and half over 5 stars

• Superb big planar performance
• Solid build with original techy design
• Comfortable fit
• Great quality practical modular cable
• Fully accessories
• Good crisp timbre and tone
• Warm, organic, fun and musical
• Amazing bass amount and response with a well controlled bass
• Well textured sound
• Amazing sub-bass extension
• Thick, clear, intimate midrange
• Amazing resolving capabilities
• Energetic, airy high range
• Good intense treble
• Superb overall technicalities
• Good soundstage width and height

• Average midrange transparency
• Slight planar timbre
• Average micro details(nitpick)
• Needs a good and powerful source matching
• Not a clinical performer (subjective)
• Competitive market and price segment
• Might be too bassy or too piercing with certain sources